Description

Definition of the MPI granular terrain node (using Chrono::Distributed).

#include <ChVehicleCosimTerrainNodeGranularMPI.h>

Inheritance diagram for chrono::vehicle::ChVehicleCosimTerrainNodeGranularMPI:

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Collaboration diagram for chrono::vehicle::ChVehicleCosimTerrainNodeGranularMPI:

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Public Member Functions
	ChVehicleCosimTerrainNodeGranularMPI (double length, double width)
	Create a Chrono::Distributed granular terrain node.

	ChVehicleCosimTerrainNodeGranularMPI (const std::string &specfile)
	Create a Chrono::Distributed granular terrain node and set parameters from the provided JSON specfile.

virtual ChSystem *	GetSystem () override
	Return a pointer to the underlying Chrono system.

void	SetNumThreads (int num_threads)
	Set the number of OpenMP threads for each Chrono::Multicore terrain simulation (default: 1).

void	SetFromSpecfile (const std::string &specfile)
	Set full terrain specification from JSON specfile.

void	SetWallThickness (double thickness)
	Set container wall thickness (default: 0.2)

void	SetGranularMaterial (double radius, double density)
	Set properties of granular material. More...

void	SetMaterialSurface (const std::shared_ptr< ChMaterialSurfaceSMC > &mat)
	Set the material properties for terrain. More...

void	UseMaterialProperties (bool flag)
	Specify whether contact coefficients are based on material properties (default: true).

void	SetContactForceModel (ChSystemSMC::ContactForceModel model)
	Set the normal contact force model (default: Hertz).

void	SetTangentialDisplacementModel (ChSystemSMC::TangentialDisplacementModel model)
	Set the tangential contact displacement model (default: OneStep).

void	SetSamplingMethod (utils::SamplingType type, double init_height, double sep_factor=1.001, bool in_layers=false)
	Set sampling method for generation of granular material. More...

void	SetProxyContactRadius (double radius)
	Set sweeping sphere radius for proxy bodies (default 5e-3). More...

virtual void	WriteCheckpoint (const std::string &filename) const override
	Write checkpoint to the specified file (which will be created in the output directory).

double	CalculatePackingDensity (double &depth)
	Estimate packing density (eta) of granular material in current configuration. More...

Public Member Functions inherited from chrono::vehicle::ChVehicleCosimTerrainNodeChrono
Type	GetType () const
	Return the type of this terrain node.

void	SetProxyFixed (bool fixed)
	Set the proxy bodies as fixed to ground.

virtual double	GetInitHeight () const override final
	Return the terrain initial height.

void	AddRigidObstacle (const RigidObstacle &obstacle)
	Add a rigid obstacle.

Public Member Functions inherited from chrono::vehicle::ChVehicleCosimTerrainNode
virtual NodeType	GetNodeType () const override
	Return the node type as NodeType::TERRAIN.

void	EnableRuntimeVisualization (bool render, double render_fps=100)
	Enable/disable run-time visualization (default: false). More...

void	SetDimensions (double length, double width)
	Set the terrain patch dimensions. More...

virtual void	Initialize () override final
	Initialize this node. More...

virtual void	Synchronize (int step_number, double time) override final
	Synchronize this node. More...

virtual void	Advance (double step_size) override final
	Advance simulation. More...

virtual void	OutputData (int frame) override final
	Output logging and debugging data.

virtual void	OutputVisualizationData (int frame) override
	Output post-processing visualization data. More...

Public Member Functions inherited from chrono::vehicle::ChVehicleCosimBaseNode
std::string	GetNodeTypeString () const
	Return the node type as a string.

bool	IsCosimNode () const
	Return true if this node is part of the co-simulation infrastructure.

void	SetStepSize (double step)
	Set the integration step size (default: 1e-4).

double	GetStepSize () const
	Get the integration step size.

void	SetOutDir (const std::string &dir_name, const std::string &suffix)
	Set the name of the output directory and an identifying suffix. More...

void	SetVerbose (bool verbose)
	Enable/disable verbose messages during simulation (default: true).

const std::string &	GetOutDirName () const
	Get the output directory name for this node.

double	GetStepExecutionTime () const
	Get the simulation execution time for the current step on this node. More...

double	GetTotalExecutionTime () const
	Get the cumulative simulation execution time on this node.

Additional Inherited Members
Public Types inherited from chrono::vehicle::ChVehicleCosimTerrainNodeChrono
enum	Type { Type::RIGID, Type::SCM, Type::GRANULAR_OMP, Type::GRANULAR_GPU, Type::GRANULAR_MPI, Type::GRANULAR_SPH, Type::UNKNOWN }
	Type of Chrono terrain. More...

Public Types inherited from chrono::vehicle::ChVehicleCosimBaseNode
enum	NodeType { NodeType::MBS_WHEELED, NodeType::MBS_TRACKED, NodeType::TERRAIN, NodeType::TIRE }
	Type of node participating in co-simulation. More...

enum	InterfaceType { InterfaceType::BODY, InterfaceType::MESH }
	Type of the tire-terrain communication interface. More...

Static Public Member Functions inherited from chrono::vehicle::ChVehicleCosimTerrainNodeChrono
static std::string	GetTypeAsString (Type type)
	Return a string describing the type of this terrain node.

static Type	GetTypeFromString (const std::string &type)
	Infer the terrain node type from the given string.

static bool	ReadSpecfile (const std::string &specfile, rapidjson::Document &d)
	Read a JSON specification file for a Chrono terrain node.

static Type	GetTypeFromSpecfile (const std::string &specfile)
	Get the terrain type from the given JSON specification file.

static ChVector2	GetSizeFromSpecfile (const std::string &specfile)
	Get the terrain dimensions (length and width) from the given JSON specification file.

Static Public Member Functions inherited from chrono::vehicle::ChVehicleCosimBaseNode
static std::string	OutputFilename (const std::string &dir, const std::string &root, const std::string &ext, int frame, int frame_digits)
	Utility function for creating an output file name. More...

Protected Types inherited from chrono::vehicle::ChVehicleCosimTerrainNodeChrono
typedef std::vector< ProxyBody >	Proxies

Protected Member Functions inherited from chrono::vehicle::ChVehicleCosimTerrainNodeChrono
	ChVehicleCosimTerrainNodeChrono (Type type, double length, double width, ChContactMethod method)
	Construct a base class terrain node. More...

virtual void	OnInitialize (unsigned int num_objects) override
	Initialize this Chrono terrain node. More...

Protected Member Functions inherited from chrono::vehicle::ChVehicleCosimTerrainNode
	ChVehicleCosimTerrainNode (double length, double width)
	Construct a terrain node to wrap a terrain patch of given length and width.

virtual void	OnSynchronize (int step_number, double time)
	Perform any additional operations after the data exchange and synchronization with the MBS node. More...

virtual void	UpdateMeshProxy (unsigned int i, MeshState &mesh_state)
	Update the state of the i-th proxy mesh. More...

Protected Member Functions inherited from chrono::vehicle::ChVehicleCosimBaseNode
	ChVehicleCosimBaseNode (const std::string &name)

void	SendGeometry (const ChVehicleGeometry &geom, int dest) const

void	RecvGeometry (ChVehicleGeometry &geom, int source) const

Protected Attributes inherited from chrono::vehicle::ChVehicleCosimTerrainNodeChrono
Type	m_type
	terrain type

ChContactMethod	m_method
	contact method (SMC or NSC)

std::shared_ptr< ChMaterialSurface >	m_material_terrain
	material properties for terrain bodies

double	m_init_height
	terrain initial height

std::vector< Proxies >	m_proxies
	proxy bodies for each object

bool	m_fixed_proxies
	are proxy bodies fixed to ground?

std::vector< RigidObstacle >	m_obstacles
	list of rigid obstacles

Protected Attributes inherited from chrono::vehicle::ChVehicleCosimTerrainNode
bool	m_render
	if true, perform run-time rendering

double	m_render_step
	time step between rendered frames

double	m_hdimX
	patch half-length (X direction)

double	m_hdimY
	patch half-width (Y direction)

bool	m_wheeled
	comm node (true: TIRE nodes, false: tracked MBS node)

InterfaceType	m_interface_type
	communication interface (body or mesh)

int	m_num_objects
	number of interacting objects

std::vector< ChVehicleGeometry::AABB >	m_aabb
	AABB of collision models for interacting objects.

std::vector< ChVehicleGeometry >	m_geometry
	contact geometry and materials for interacting objects

std::vector< double >	m_load_mass
	vertical load on interacting objects

std::vector< int >	m_obj_map
	mapping from interacting object to shape

std::vector< MeshState >	m_mesh_state
	mesh state (used for MESH communication)

std::vector< BodyState >	m_rigid_state
	rigid state (used for BODY communication interface)

std::vector< MeshContact >	m_mesh_contact
	mesh contact forces (used for MESH communication interface)

std::vector< TerrainForce >	m_rigid_contact
	rigid contact force (used for BODY communication interface)

Protected Attributes inherited from chrono::vehicle::ChVehicleCosimBaseNode
int	m_rank
	MPI rank of this node (in MPI_COMM_WORLD)

double	m_step_size
	integration step size

std::string	m_name
	name of the node

std::string	m_out_dir
	top-level output directory

std::string	m_node_out_dir
	node-specific output directory

std::ofstream	m_outf
	output file stream

unsigned int	m_num_wheeled_mbs_nodes

unsigned int	m_num_tracked_mbs_nodes

unsigned int	m_num_terrain_nodes

unsigned int	m_num_tire_nodes

ChTimer< double >	m_timer
	timer for integration cost

double	m_cum_sim_time
	cumulative integration cost

bool	m_verbose
	verbose messages during simulation?

Static Protected Attributes inherited from chrono::vehicle::ChVehicleCosimBaseNode
static const double	m_gacc = -9.81

Member Function Documentation

◆ CalculatePackingDensity()

double chrono::vehicle::ChVehicleCosimTerrainNodeGranularMPI::CalculatePackingDensity ( double & depth )

Estimate packing density (eta) of granular material in current configuration.

Note that porosity is phi=1-eta and void ratio is e=(1-eta)/eta=phi/(1-phi). The function also returns the current depth of granular material.

◆ SetGranularMaterial()

void chrono::vehicle::ChVehicleCosimTerrainNodeGranularMPI::SetGranularMaterial	(	double	radius,
		double	density
	)

Set properties of granular material.

Parameters

radius	particle radius (default: 0.01)
density	particle material density (default: 2000)

◆ SetMaterialSurface()

void chrono::vehicle::ChVehicleCosimTerrainNodeGranularMPI::SetMaterialSurface ( const std::shared_ptr< ChMaterialSurfaceSMC > & mat )

Set the material properties for terrain.

These parameters characterize the material for the container and the granular material. Tire contact material is received from the MBS node.

◆ SetProxyContactRadius()

void chrono::vehicle::ChVehicleCosimTerrainNodeGranularMPI::SetProxyContactRadius ( double radius )

inline

Set sweeping sphere radius for proxy bodies (default 5e-3).

This value is used as a "thickness" for collision meshes (a non-zero value can improve robustness of the collision detection algorithm).

◆ SetSamplingMethod()

void chrono::vehicle::ChVehicleCosimTerrainNodeGranularMPI::SetSamplingMethod	(	utils::SamplingType	type,
		double	init_height,
		double	sep_factor = `1.001`,
		bool	in_layers = `false`
	)

Set sampling method for generation of granular material.

The granular material is created in the volume defined by the x-y dimensions of the terrain patch and the specified initial height, using the specified sampling type, layer by layer or all at once. Note: for correct HCP, do not initialize in layers!